A case of Verner-Morrison syndrome with solitary VIPoma and an incidental serous mucinous adenoma
Rupa Ahluwalia, Aung Mon & Jiten Vora
Introduction: Neuroendocrine tumors (NET) are very rare and often present a diagnostic challenge. They are often misdiagnosed due to non-specific symptoms. We report a rare case of NET presenting to a non endocrine unit.
Case: A 72-year-old Caucasian female was referred for refractory diarrhoea with hypokalaemia. In addition, there was history of significant weight loss over few months.
She had past medical history of diabetes, hypertension and gastroesophageal reflux disease.
Given her symptoms, she was referred to the gastroenterology department.
Her baseline bloods were normal albeit a low potassium. Colonoscopy revealed a benign rectal ulcer. Computed tomography of the abdomen showed a pancreatic tumour measuring 2.6×2.7×2.4 cm. This was further confirmed on magnetic resonance imaging.
After ruling out primary pancreatic malignancy, she underwent further investigations for a suspected NET.
Baseline fasting gut hormone profile identified elevated plasma vasoactive intestinal polypeptide (VIP) (99, reference range 030 pmol/l) and chromogranin A levels. Her 24 h urinary 5-HIAA levels were normal.
The tumor confirmed somatostatin receptor positivity on radiolabelled Octreotide scanning with no evidence of metastasis.
Given her symptoms with raised VIP levels in presence of a pancreatic tumour, a diagnosis of VernerMorrison syndrome was made.
She was commenced on subcutaneous somatostatin analogue therapy for symptomatic relief. Later, she underwent left radical pancreatectomy with splenectomy. A separate incidental serous mucinous adenoma was identified on histology.
She remains asymptomatic off treatment, 6 months post surgery.
Conclusion: VernerMorrison syndrome is the combination of watery diarrhoea, hypokalaemia and acidosis due to secretion of VIP from a neuroendocrine pancreatic tumour. VIPomas account for <10% of islet cell tumors.
We report a rare case of VIPoma and also highlight the need to remain cognisant of NETs as possible differential diagnosis for persistent diarrhoea.